Saw dust generated during use of rotary power tools is a major problem. First, such dust may cause user airway irritation or possible explosion if ignited by a flame or a spark. In addition, saw dust is very difficult to clean-up and as such, results in the woodworker spending an inordinate amount of time cleaning up the work area. Further, saw dust generated while making a cut may impair user visibility of a work piece and thus, decreased cut precision. Therefore, saw dust generation needs to be controlled to minimize the aforementioned adverse effects associated with woodworking as well as to improve cutting visibility allowing for a user to make more precise cuts.
Currently, saw dust generation associated with use of rotary power tools may be controlled by use of a respirator or a dust collection system. Use of a respirator prevents a woodworker from being exposed to dust particles and thereby eliminates the possibility of user airway irritation. However, such device does not assist the woodworker in decreasing the amount of time associated with clean-up or visibility of the work piece. In contrast, the dust collection system including a hose-pipe-suction-filter system for catching chips and dust at the source reduces the possibility of user airway irritation and time spent cleaning up as well as to increase visibility of the work piece. Typically, a woodworker may employ a central dust collection system which may be attached to various types of power tools or an individual dust collection system which is a component of a particular tool.
Although dust collection systems presently known in the art have greatly reduced the possibility of user airway irritation and amount of clean-up associated with the use of rotary power tools as well as enhanced user visibility, many limitations are still associated with such systems. A central dust collection system, for instance, is often quite large, expensive to purchase and may require modifications to be made to the work area (i.e. addition of a 220V electrical supply and ductwork) prior to operation. Further, an individual dust collection system which is a component of a particular tool (i.e. a hand-held circular saw) is limited by the need to attach a vacuum hose to the dust port confining user movement of the saw and negating the benefit of a cordless tool.
Therefore, it would be desirable to develop a hand-held circular saw with an integrated dust collection system which includes a variable dust chute allowing dust and debris to be collected in a dust collection bag or circulated through the path of a blade guard of the circular saw preventing saw dust and debris from being blown upward toward the user.